Alteration of the T-cell receptor repertoire in A.CA mice expressing an Ead transgene.

In an effort to generate an A.CA mouse expressing Ed, the Ead gene has been introduced into A.CA mice which lack the major histocompatibility complex (MHC) class II E molecule. Flow cytometric analysis shows cell surface expression of the E alpha chain on lymphocytes and macrophages in the transgenic mice. Analysis of T-cell receptor (Tcr) genes deleted in some E-expressing mouse strains demonstrates that T cells expressing Tcrb-V5 are partially deleted in these transgenic mice while those expressing Tcrb-V8 and Tcrb-11 are not. In addition, the expressed E alpha d chain can promote Mycoplasma arthriditis mitogen (MAM)-induced T-cell proliferation. The expression of the E alpha chain, presumably as an A beta fE alpha d heterodimer, can alter the peripheral T-cell repertoire and T-cell reactivity to a microbial superantigen.